The invention relates to acetylenic diol alkylene oxide adducts, or alkoxylated acetylenic diols, and their manufacture and their use to reduce the surface tension in aqueous-based and/or non-aqueous based process solutions.
The ability to reduce the surface tension of water is of great importance in waterborne coatings, inks, adhesives, agricultural formulations, and process solutions such as rinse, pre-treatment, or other solutions for the electronics industry because decreased surface tension translates to enhanced substrate wetting in actual formulations. Surface tension reduction in water-based systems is generally achieved through the addition of surfactants. Equilibrium surface tension performance is important when the system is at rest, though the ability to reduce surface tension under dynamic conditions is of great importance in applications where high surface creation rates are used, i.e., spin coating, rolling, spray coating, and the like. Dynamic surface tension provides a measure of the ability of the solution to lower surface tension and provide wetting under high speed application conditions. Further, in certain applications such as during spray application, it is advantageous that the surfactant reduces the surface tension of the formulation in a manner that minimizes the problem of bubble generation and foaming. Foaming and bubble generation may lead to defects. Consequently, considerable efforts have been made in the electronics and other industries towards solving the foaming problem.
In the electronics industry, defects are a major limiting factor for production yield and device function, particularly when the device sizes are reduced and wafer sizes are enlarged to 300 mm. The term “defects”, as used herein, relates to defects that may reduce the yield, or cause the loss, of the semiconductor device such as the collapse of the photoresist pattern on the substrate surface; roughness in the photoresist lines such as “line width roughness” or “line edge roughness”, particulates introduced onto the substrate resulting from processing such as lithography, etching, stripping, and chemical mechanical planarization (CMP) residues; particulates either indigenous to or resulting from manufacturing processes; pattern imperfections such as closed or partially open or blocked contacts or vias; line width variations; and defects resulting from poor adhesion of the resist to the substrate surface.
The drive to reduce defects—thereby improving yield—presents new challenges to the manufacturing steps within the production of the semiconductor device, namely, the lithography, etching, stripping, and chemical-mechanical planarization (CMP) processes. The lithography process generally involves coating a substrate with a positive or negative photoresist, exposing the substrate to a radiation source to provide an image, and developing the substrate to form a patterned photoresist layer on the substrate. This patterned layer acts as a mask for subsequent substrate patterning processes such as etching, doping, and/or coating with metals, other semiconductor materials, or insulating materials. The etching process generally involves removing the surface of the substrate that is not protected by the patterned photoresist using a chemical or plasma etchant thereby exposing the underlying surface for further processing. The stripping process generally involves removing the cross-linked, photoresist pattern from the substrate via wet stripping or oxygen plasma ashing. The CMP process generally involves polishing the surface of the substrate to maintain flatness during processing. All of the aforementioned processes typically employ a rinse step to remove any particulate material that is generated from, or is a by-product of, these processes.
Traditional nonionic surfactants such as alkylphenol or alcohol ethoxylates, and ethylene oxide (EO)/propylene oxide (PO) copolymers have excellent equilibrium surface tension performance but are generally characterized as having poor dynamic surface tension reduction. In contrast, certain anionic surfactants such as sodium dialkyl sulfosuccinates can provide good dynamic results, but these are very foamy and impart water sensitivity to the finished coating.
Surfactants based on acetylenic glycols such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol (1) and its ethoxylates (2) are known for their good balance of equilibrium and dynamic surface-tension-reducing capabilities with few of the negative features of traditional nonionic and anionic surfactants.

For many applications it would be desirable to produce acetylenic diol derivatives which have alternative properties. For example, in applications in which excellent dynamic performance is required, it is often desirable to have a surfactant which has higher critical aggregation concentration (solubility limit or critical micelle concentration) because higher bulk surfactant concentrations lead to a higher diffusive flux of surfactant to newly created surface, and consequently lower dynamic surface tension. Traditionally, acetylenic diol surfactants with higher water solubility have been obtained by reaction of the parent with ethylene oxide; greater degrees of ethoxylation provide greater water solubility. Unfortunately, increasing the level of ethoxylation also introduces a tendency to foam, introducing inefficiencies during formulation, defects during application, and process issues in other applications.
Low dynamic surface tension is of great importance in the application of waterborne coatings. In an article, Schwartz, J. “The Importance of Low Dynamic Surface Tension in Waterborne Coatings”, Journal of Coatings Technology, September 1992, there is a discussion of surface tension properties in waterborne coatings and a discussion of dynamic surface tension in such coatings. Equilibrium and dynamic surface tension were evaluated for several surface active agents. It is pointed out that low dynamic surface tension is an important factor in achieving superior film formation in waterborne coatings. Dynamic coating application methods require surfactants with low dynamic surface tensions in order to prevent defects such as retraction, craters, and foam.
In applications which require good dynamic performance and low foaming, acetylenic glycol-based surfactants have become industry standards. The following patents and articles describe various acetylenic alcohols and their ethoxylates as surface active agents:
U.S. Pat. No. 3,268,593 and Leeds, et al, I&EC Product Research and Development 1965, 4, 237, disclose ethylene oxide adducts of tertiary acetylenic alcohols represented by the structural formula

wherein R1 and R4 are alkyl radicals having from 3-10 carbon atoms and R2 and R3 are methyl or ethyl and x and y have a sum in the range of 3 to 60, inclusive. Specific ethylene oxide adducts include the ethylene oxide adducts of 3-methyl-1-nonyn-3-ol, 7,10-dimethyl-8-hexadecyne-7,10-diol; 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 4,7-dimethyl-5-decyne-4,7-diol. Preferably, the ethylene oxide adducts range from 3 to 20 units. Also disclosed is a process for the manufacture of materials of this type using trialkylamine catalysts.
U.S. Pat. No. 4,117,249 discloses 3 to 30 mole ethylene oxide (EO) adducts of acetylenic glycols represented by the structural formula
wherein R is hydrogen or an alkenyl radical. The acetylenic glycols are acknowledged as having utility as surface active agents, dispersants, antifoaming nonionic agents, and viscosity stabilizers.
U.S. Pat. No. 5,650,543 discloses ethoxylated acetylenic glycols of the form
where x and y are integers and the sum is from 2-50. These surfactants are notable because they impart an ability to formulate coating and ink compositions capable of high speed application.
JP 2636954 B2 discloses propylene oxide adducts of formula
where R=C1-8 alkyl; m+n=integer 1 to 100. These compounds are prepared by reacting acetylenic glycols and propylene oxide in the presence of Lewis acid catalysts such as BF3. It is stated that amine catalysts are inactive for the addition of propylene oxide to acetylenic diols. The propylene oxide adducts are said to be useful as wettability improvers for antirust oil, antifoamers, spreaders for pesticides, and wetting agents for adhesives. They are effective in improving wettability of oils and have improved antifoaming ability.
JP 2621662 B2 describes dye or developing agent dispersions for thermal recording paper containing propylene oxide (PO) derivatives of an acetylenic diol of the form
where R1 and R2 are —CH3, —C2H5, —C4H9; R3 and R4 are —(OC3H 4)mOH, or —OH where m is an integer 1-10.
JP 04071894 A describes coating solutions containing a dispersion of a colorless electron donating dye precursor and a dispersion of developer. At least one of them contains at least one type of wax having a melting point of at least 60° C. and at least one EO or PO derivative of an acetylenic diol of the formula
where R1 and R4 each represent methyl, ethyl, propyl, or butyl and R2 and R3 are each —(OC2H5)nOH, or —(OC3H6)nOH (n is 1-10), or OH, mixed and dispersed.
JP 2569377 B2 discloses a recording material containing dispersions of a substantially colorless electron donating dye precursor and a developer. When at least one of these dispersions is prepared, at least one of the compounds
where R3 and R6=methyl, ethyl, propyl or butyl; and R4 and R5=—(OC2H4)mOH, —(OC3H6)mOH (where m=an integer of 1-10) or —OH is added.
JP 09150577 A discloses a heat sensitive recording medium which contains in the heat sensitive layer a leuco dye and 0.1-1.0 wt % of an ethoxylate or propoxylate of an acetylenic glycol of the form
where R1=methyl, ethyl, propyl or butyl; R2=hydrogen or methyl; and n and m=1-10.
JP 04091168 A discloses silica which has been surface treated with compounds of the form
where R1=1-8C alkyl, A=2-3C alkylene glycol residue, R1 and A in a molecule may be the same or different, x and y=each an integer of 0-25.
JP 06279081 A describes a manufacturing process for a cement mortar-concrete hardening material to which 0.5-10 wt. % an acetylenic alcohol or diol alkoxylate is added together with fluorine group surfactants and/or silicon group surfactants. The acetylenic material can be expressed by the formula
where R1=H or —C(R2)(R3)(O(AO)nH); R2 and R3=1-8 C alkyl radicals, A=2-3 C alkylene radicals and n=0-30.
JP 03063187 A discloses the use of acetylenic glycol ethylene oxide and/or propylene oxide addition products in concentrated aqueous fountain solution compositions for offset printing. In one example, the 8 to 12 mole ethylene oxide/1 to 2 mole propylene oxide adduct of 3,5-dimethyl-4-octyne-3,5-diol is used in a fountain solution. Other examples illustrate the use of only ethylene oxide derivatives of acetylenic diols.
Although acetylenic diol derivatives containing both ethylene oxide (EO) and propylene oxide (PO) have been taught as a general class of materials, usually as potential extensions of work which had been performed with ethylene oxide derivatives, no actual examples of an acetylenic diol EO/PO derivative based upon 2,4,7,9-tetramethyl-5-decyne-4,7-diol or 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol have been prepared and evaluated. There are no disclosures of any process which could be used to prepare materials of this type.